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THERMOSTAT. NQ. 351,719. Patented Oct. 26, 1886.

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UNITED STATES PATENT OEEICEo LAVSON B. STONE, OF MARBLEHEAD, MASS., ASSI NOR TO THE AMERICAN AUTOMATIC FIRE ALARM ASSOCIATION, OF PORTLAND, ME.

THERMOSTAT.

SPECIFICATION forming part of Letters Patent No. 35l ,719, dated October 26,"1886. Application filed April 19, 1-8i. Strial No. 199,311. (No model.)

To all whom it may concern: n

Be it known that I, LAWSON B. STONE, a citizen of the United States, residing at Marblehead, in the county of Essex and State of Massach usetts, have invented certain new and ufseful Improvements in Thermostats; and l do hereby declare the following to he a full, clear, and exact description of the invention, such as will enable others skilled in the art to which 1o it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or ignres of reference marked thereon, which form a part of this specification.

This invention relates to thermostals which employ a spring as the thermostatic agent, and it consists, chietly,in the combination of such a spring and the electric circuit, of which it forms one terminal, with another spring, the 2o other terminal of said circuit attached to said spring, and an adj usting-screw bearing against one of said springs to regulate the distance between said terminals, as hereinafter set forth `und claimed. V

The said invention also relates to certain additional features of construction and combination, also hereinafter set forth and claimed.

The drawings accompanying this specification represent, in Figure 1, a vertical central section and Fig. 2 a sectional plan, of ajournal-thermostat embodying my invention. Fig. 3 is an enlarged view showing the manner of mounting the adjust-able terminal, while Fig. "4t is a sectional elevation showing a modifica- 35 tion. Fig. 5 is a horizontal section, wherein the Bourdon spring isinsulatcd as a terminal.

Fig. 6 represents a sectional detail view of a modified form of terminal arranged so that the expansion of the Bourdon spring will open 4o the circuit instead of closing it.

In said drawings, A represents a piece of shafting suitably mounted in the bearing B. Upon the latter is atlixed the journaltherniostat, which consists, primarily, of a hollow 4 5 circular metallic box or case, C, surmounted by and covered with the cap D. Centrally 1ocated thereof and secured to said box is a hollow post or tube, E, which extends outwardly, and is of a length to suit requirements or the 5o location of the thermostat. In the present instance this tube is fitted into the journal-box and approaches very closely the periphery of the shaft. In order tomake a close metallic connection, the more readily and efficiently to convey to the thermostat the heat from said. shaft and bearing should it at any time become excessive, I have longitudinally -kerf-cnt or split said tube at a, and hence when it is thrust into its proper position in the bearing the sides of the tube are compressed, and thus 6o brought into close contact with the surrounding metallic surface.

By the use of a hollow' post the thermostat can readily embody in its construction an oilcup, since the lubricant supplied from the cup F, whichis secured to and surmounts the cap D of the thern'xostat, is conveyed downward through the bore b ofthe tube E, and thence to the journal-bearing and its shaft. Thus while the thermostat supplies the oil, it is in readi- 7o ness to announce at any time whether the bearing is properly lubricated or not.

The portionsof this apparatus operated thermally consist of a Bourdon spring, c, (the construction and operation of which is well known among those skilled in the art,) one end of which is firmly soldered to the upper part of the hollow post E. Directly opposite the free end or extremity d of this Bourdon spring is disposed the adjustable terminale, so in an electric circuit. This terminal is mounted up'on a plate-spring, j", which isr secured to the case B exteriorly ol' the Bourdon spring, and bent to conform somewhat to the curve ot' the box within which it is contained. The free end of this plate-spring f is bored to admit a hollow sleeve, g,securely 'fastened thereto. Said sleeve is made of any suitable insulating material interiorly,screwthreaded, to receive and hold the metallic terminal, pointed interiorly,

and which terminates exteriorly in a binding-post, h. Furthermore, the iuclosing box or case C is bored at fi to permit unimpeded movement ot' the terminal e and its insulatingsleeve g, while arranged ldiametrically opposite and in metallic connection with said case -C is afiixed a second binding-post, IL', the terminal of which is the free end l of the Bourdon spring. Thus the wires (not shown.) connecting with the posts h h may extend to any suit- IO@ able or convenient place or room in which the alarm is to ybe given, and are constantly in piace to be electrically induced, so 'that when the two terminals d and c are united by the movement of the Bourdon spring, due to increase in the temperature which actuates it, the circuit is closed and the thermostatic alarm apparatus performs its office.

Hitherto in the arrangement of t-herinostats of the class before premised the activity or range of movement in said Bourdon spring or the thermal temperature at which the circuit `will be operated has been dependent upon the coeiicient of expansion of the contents of the spring or on the strength of the material composing said spring. In some instances the t'ree end of the spring has been encumbered, in order to overcome the tension of a spring' terminal, which acts to oppose its movement. To overcome these defects and enable the Bourdon spring to be made of material of any desired strength, and not necessarily iill it with certain easily-expansible gas or iiuid, or a combination of the two in order to regulate its action, I have adjustably mounted one of the terminals upon a spring, which, by means of the screw s, engaged in the case C, can be caused to retreat or advance, and thus carry the terminal from or toward the Bourdon spring. Consequentlyitis evident that greater extremes of movement is permitted thelatter, and it will be compelled to advance a greater or less distance to operate the circuit, either of which movements must be attendant upon or caused by a greater or less degree of heat.

In lieu of insulating the spring-mounted terminal, as shown, a ver practicable modifica` tion is that represented in Fig. 5, in which the plate-spring is omitted and the Bourdon spring insulated. By this alteration the same adjustment in the thermal temperature at which the thermostat becomes active is obtained. This variation in the active thermal temperature is secured by means of the screw s, engaging in the thermostat case,and which is also in metallic connection with the post 71, the Bourdon spring, on the other-hand, being insulated, together' with the post lz, with which it is electrically connected. By either construction in the expansion ofthe gas within the Bourdon spring and the straightening of the latter sliding metallic contact is effected between the terminals to operate an electric circuit. Again, by loeating this adjustable terminal opposite the free extremity of the Bourdon spring, Where its action or movement is the greatest, any extreme is easily and readily obtained, if deof said spring is unimsired, While the action peded, and yet can be accurately adjusted. This thermostat in the present drawings is shown as constructed to be on an open circuit; but the alternative construction to operate a closed circuit is equally as practicable, since by extending the terminal s or e with an offset or bend to place the contact-point upon the concave surface of the Bourdon spring,the tivo normally in contact, any expansion or movement of said spring due to increase in the thermal temperature will open the circuit and cause an alarm.

In the present instance I have shown my thermostat as embodyingan oil-cup; but Idesire not to be limited to this precise arrangement, since the supporting-rod or conductor E may besolid and the oil-cup omitted. Again, the hollow post or rod E may be replaced by an ordinary scre\v,m, and the thermostat afxed elsewhere.

As before premised,

| l i this device may be l caused to operate either-.an open or closed eleci tric system, and therefore applicable as a thermostat to other locations and positions, and especially alarrn-circuits.

In Fig. 6 the terminal e is hook-shaped, so that it may come within the curve of the Bourl don spring c, andbe normally in Contact with the inner face of the free end of said spring. I The expansion of the latter opens the circuit.

I claiml. The combination of a thermostatic spring and the circuit of which it forms one terminal f with another spring,

circuit attached to saidspring, and an adjusting-screw bearing against one of said springs and regulating the distance of said terminals from each other.

2. In combination with post E and case C, the Bourdon spring c, attached to said post, a spring, f, attached to said case, a contact, e, carried by the latter spring, and an adjustingscrew, s, acting againstspringj", substantially as set forth.

B. A Bourdon spring, c, an adjustable terminal, c, opposed thereto, an insulating-sleeve surrounding said terminal, a spring to which said sleeve is attached,andan adjnstingscrew acting against the latter spring to adjust. the terminal, substantially as set forth.

In testimony whereof I affix my signature in presence of two witnesses.

. LAWSON B. STONE.

Witnesses:

H. E. LoDoi-, F. GURTts.

the other terminal of said 

